356 research outputs found
Aspects of Axion Phenomenology in a slice of AdS_5
Motivated by multi-throat considerations, we study the phenomenological
implications of a bulk axion in a slice of AdS_5 with a large extra dimension:
k~0.01 eV, kR > 1. In particular, we compare axion physics with a warped
geometry to axions in flat compactifications. As in flat compactification
scenarios, we find that the mass of the axion can become independent from the
underlying Peccei-Quinn scale. Surprisingly, we find that in warped extra
dimensions the axion's invisibility, cosmological viability, and basic
phenomenology remain essentially unaltered in comparison to axions in flat
compactifications.Comment: 25 pages, 9 figure
Oblique amplitude modulation of dust-acoustic plasma waves
Theoretical and numerical studies are presented of the nonlinear amplitude
modulation of dust-acoustic (DA) waves propagating in an unmagnetized three
component, weakly-coupled, fully ionized plasma consisting of electrons,
positive ions and charged dust particles, considering perturbations oblique to
the carrier wave propagation direction. The stability analysis, based on a
nonlinear Schroedinger-type equation (NLSE), shows that the wave may become
unstable; the stability criteria depend on the angle between the
modulation and propagation directions. Explicit expressions for the instability
rate and threshold have been obtained in terms of the dispersion laws of the
system. The possibility and conditions for the existence of different types of
localized excitations have also been discussed.Comment: 21 pages, 6 figures, to appear in Physica Script
Citizenship:Contrasting Dynamics at the Interface of Integration and Constitutionalism
EUDO Citizenship ObservatoryThis paper explores the different ways in which citizenship has played a role in polity formation in the
context of the European Union. It focuses on both the ‘integration’ and the ‘constitution’ dimensions.
The paper thus has two substantive sections. The first addresses the role of citizenship of the Union,
examining the dynamic relationship between this concept, the role of the Court of Justice, and the free
movement dynamic of EU law. The second turns to citizenship in the Union, looking at some recent
political developments under which concepts of citizenship, and democratic membership as a key
dimension of citizenship, have been given greater prominence. One key finding of the paper is that
there is a tension between citizenship of the Union, as part of the EU's ‘old’ incremental
constitutionalism based on the constitutionalisation of the existing Treaties, and citizenship in the
Union, where the possibilities of a ‘new’ constitutionalism based on renewed constitutional documents
have yet to be fully realise
Simulating Quantum Dynamics with Entanglement Mean Field Theory
Exactly solvable many-body systems are few and far between, and the utility
of approximate methods cannot be overestimated. Entanglement mean field theory
is an approximate method to handle such systems. While mean field theories
reduce the many-body system to an effective single-body one, entanglement mean
field theory reduces it to a two-body system. And in contrast to mean field
theories where the self-consistency equations are in terms of single-site
physical parameters, those in entanglement mean field theory are in terms of
both single- and two-site parameters. Hitherto, the theory has been applied to
predict properties of the static states, like ground and thermal states, of
many-body systems. Here we give a method to employ it to predict properties of
time-evolved states. The predictions are then compared with known results of
paradigmatic spin Hamiltonians.Comment: 8 pages, 3 figure
A fundamental test of the Higgs Yukawa coupling at RHIC in A+A collisions
Searches for the intermediate boson, , the heavy quantum of the Weak
Interaction, via its semi-leptonic decay, , in the 1970's instead
discovered unexpectedly large hadron production at high , notably ,
which provided a huge background of from internal and external
conversions. Methods developed at the CERN ISR which led to the discovery of
direct-single- in 1974, later determined to be from the semi-leptonic
decay of charm which had not yet been discovered, were used by PHENIX at RHIC
to make precision measurements of heavy quark production in p-p and Au+Au
collisions, leading to the puzzle of apparent equal suppression of light and
heavy quarks in the QGP. If the Higgs mechanism gives mass to gauge bosons but
not to fermions, then a proposal that all 6 quarks are nearly massless in a
QGP, which would resolve the puzzle, can not be excluded. This proposal can be
tested with future measurements of heavy quark correlations in A+A collisionsComment: 12 pages, 16 figures, 26th Winter Workshop on Nuclear Dynamics, Ocho
Rios, Jamaica WI, January 2-9, 2010. Corrected citation of 1974 direct single
lepton discover
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